1. Field of the Invention
This invention relates to pipe-bending tools and, more particularly, to methods of gauging the angle to which pipes are bent.
2. Description of the Prior Art
It is often necessary for a person installing pipe or electrical conduits to bend the pipe or conduit to meet the needs of a particular installation job. Existing pipe-bending tools utilize a bending head having a curved surface against which the pipe is made to conform so that the angle to which the pipe is bent is proportional to the length of contact between the pipe and the curved surface.
Existing methods of gauging the angle to which the pipe is to be bent require the installer either to visually align the pipe with indicia on the pipe-bending head or to adjust a stopping device located on the pipe-bending head itself which either limits movement of the bending head or limits the length of contact between the pipe and the curved surface.
When the visual alignment method is used, the installer must be located within view of the indicia on the pipe-bending head and carefully apply enough force to bend the pipe around the bending head until it lines up with the indicia which corresponds to the desired bending angle. If too much force is applied by the installer, the pipe will bend beyond the desired bending angle, resulting in loss of time and material. The degree of care required to accurately gauge bends significantly decreases the speed at which pipe can be bent using the visual alignment method.
Existing methods of stopping the pipe when it is bent to the desired angle require the installer to adjust a stopping device on the pipe-bending head before the pipe is placed in the tool. These adjustments will typically require the installer to: loosen a screw or bolt which secures the stopping device in place; set the stopping device for the desired bending angle by fitting it into a notch built into the bending head or aligning it with indicia located on the tool; and finally, tighten a screw or bolt to resecure the stopping device. Because stopping devices which limit the length of contact between the pipe and the curved surface contact the pipe relatively close to the center of the bending arc, any error in setting these stopping devices will result in a magnified error in the actual angle to which the pipe is bent. Stopping devices which limit movement of the bending head itself generally cannot be used on soft surfaces typically found at construction sites. Also, they are inherently inaccurate since the stop member is located on the bending head itself.